1. Field of the Invention
The present invention relates to an image scaling control circuit and a method thereof. More particularly, the present invention relates to the architecture of an image scaling control circuit for scaling an image into at least two images with different scaling ratios at the same time, and a memory control method thereof.
2. Description of Related Art
Recently, flat panel displays (FPDs), for example, LCDs are widely used. Along with the improvement in semiconductor technology, an LCD has various advantages, such as low electric power consumption, light and thin, high resolution, high color saturation and long life span. Therefore, LCDs are widely used in electronic products indispensable to people's life, such as the liquid crystal screens of notebooks or desktop computers and LCD TVs.
As an FPD usually has only one rated resolution, an image scaling circuit must be provided between an input image signal and a panel to scale the resolution of the input image signal to fit the rated resolution of the FPD. For example, if the resolution of the input image signal is 640*480 while the rated resolution of the FPD is 1024*768, the image scaling circuit is needed to convert the input image signal with the resolution of 640*480 into a signal with the resolution of 1024*768 required by the panel through an interpolation operation.
Generally, a set of line buffer memories are built in a conventional image scaling circuit for the use of operation registration of the image scaling circuit. When applied to a dual-display panel, a digital camera or a dual-screen handset, etc. with different resolutions, and the same image must be scaled to two images with different ratios, two sets of image scaling circuits are needed, wherein each set includes a set of line buffer memories. As such, the cost is undoubtedly increased. In addition, if two sets of image scaling circuits should be disposed on a circuit board, the circuit layout will unavoidably become more difficult, and interference may occur easily.
Therefore, an apparatus and a method thereof are needed to solve the above problems, wherein the two sets of image scaling circuits are integrated and share a set of line buffer memories.